<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8" />
    <title>React 实例</title>
    <script src="https://cdn.staticfile.org/react/16.4.0/umd/react.development.js"></script>
    <script src="https://cdn.staticfile.org/react-dom/16.4.0/umd/react-dom.development.js"></script>
    <script src="https://cdn.staticfile.org/babel-standalone/6.26.0/babel.min.js"></script>
</head>
<body>
<div id="example"></div>

<script type="text/babel">
    function ListItem(props) {
        // 对啦！这里不需要指定key:
        return <li>{props.value}</li>;
    }

    function NumberList(props) {
        const numbers = props.numbers;
        const listItems = numbers.map((number) =>
                    // 又对啦！key应该在数组的上下文中被指定
                <ListItem key={number.toString()}
        value={number} />
    );
        return (
                <ul>
                {listItems}
                </ul>
    );
    }

    const numbers = [1, 2, 3, 4, 5];
    ReactDOM.render(
    <NumberList numbers={numbers} />,
            document.getElementById('example')
    );
</script>

</body>
</html>